[RE-wrenches] Outback VFX input voltage cycling

[R Young]

I'm having a problem with an Outback VFX3524 inverter installed on an  
E-panel in a remote off-grid location. Voltage at the inverter input  
terminals is fluctuating between 110 & 140+ volts continuously. AC in  
will not connect so batteries can't charge. Output voltage measured  
at the inverter output terminals is steady at 122v.  When all  
household loads are turned off the input terminal voltage stabilizes  
but AC In still does not connect.

Generator does not seem to be at fault as output measured at the gen.  
is stable even under load. System was working for about 1 1/2 years  
but under new ownership has been badly monitored and batteries have  
become totally discharged.

I'm trying to determine if this is a circuit board problem so I can  
perform a rescue mission by pulling some boards from an in-stock  
inverter, Outback tech support are on holidays. Anyone had a similar  
problem?

Ron Young